To route S3 traffic privately from within a VPC, AWS provides Gateway VPC Endpoints for Amazon S3.
These allow private connectivity to S3 without traversing the public internet or requiring an Internet Gateway.
From AWS Documentation:
"A gateway endpoint enables you to privately connect your VPC to supported AWS services such as Amazon S3 and DynamoDB without requiring an Internet Gateway, NAT device, or public IP." (Source: Amazon VPC User Guide - Gateway Endpoints) Why A is correct:
* Gateway VPC endpoints route S3 traffic internally within the AWS network.
* Improves security and data privacy while reducing exposure to the public internet.
* Requires only a simple route table modification and IAM policy configuration.
Why other options are incorrect:
* B: S3 is a regional service; you cannot "move" it inside a VPC.
* C: Access points do not change the routing path; still uses S3 endpoints.
* D: AWS Direct Connect is for hybrid environments, not intra-AWS private connectivity.
References:
Amazon VPC User Guide - "Gateway Endpoints for Amazon S3"
AWS Well-Architected Framework - Security Pillar
AWS Networking Best Practices

AWS Transit Gateway is the correct architecture for connecting a very large number of VPCs in a scalable hub-and-spoke model. VPC peering between more than 1,000 VPCs would create an unmanageable mesh of peering connections and route table updates. VPN tunnels are intended for encrypted connectivity over external networks, not for efficient VPC-to-VPC communication at this scale. A Direct Connect gateway is used for connecting on-premises networks to AWS and is not the right mechanism for attaching every VPC through public VIFs. Transit Gateway supports VPC attachments and centralized route tables, which makes it the operationally scalable and high- performing choice for communication among many VPCs.

Option B: FSx for Lustre is designed for HPC workloads with high IOPS.
* Option E: A cluster placement group ensures low-latency networking for HPC analytics workloads.
* Option A: Amazon EFS is not optimized for HPC.
* Option D: Mountpoint for S3 does not meet high IOPS needs.

In Amazon EKS, Kubernetes stores objects such as Secrets in the cluster's etcd key-value store. By default, Kubernetes Secrets are base64-encoded and are not automatically encrypted at the application object level unless encryption is configured. Amazon EKS provides a managed capability to encrypt Kubernetes Secrets at rest in etcd using AWS Key Management Service (KMS). The requirement explicitly states that "all secrets that are stored in Amazon EKS must be encrypted in the Kubernetes etcd key-value store," which maps directly to enabling EKS secrets encryption with a customer-managed KMS key.
Option B is exactly this: create a KMS key and enable EKS KMS secrets encryption on the cluster. With this enabled, EKS uses envelope encryption so that Secrets are encrypted when stored in etcd, and decrypt operations are controlled through KMS permissions. This is the standard, AWS-native method that fulfills the requirement without requiring application changes or external secret stores for the encryption-at-rest requirement in etcd.
Option A (Secrets Manager) is a strong service for secret lifecycle management and rotation, but it does not by itself guarantee that Kubernetes Secrets stored in etcd are encrypted unless EKS secrets encryption is also enabled or the cluster avoids storing secrets in etcd entirely. The question specifically targets etcd encryption.
Option C is unrelated: the EBS CSI driver concerns persistent volumes, not etcd secret encryption. Option D concerns EBS volume encryption and a specific AWS-managed key alias used for EBS; it also does not address etcd encryption for Kubernetes Secrets.
Therefore, B is the correct solution because it directly enables encryption of Kubernetes Secrets within etcd using KMS.

* A. Mutual TLS: Provides secure communication but does not integrate with AWS credential exchange.
* B. AWS Signature v4: Requires direct integration with AWS and is less secure for external systems.
* C. Kerberos: Not natively supported for AWS API authentication.
* D. IAM Roles Anywhere: Enables AWS API access using X.509 certificates without long-term credentials.
References: IAM Roles Anywhere